Monk's Spade Mind Blade( Secrets of Sarlona, p. 118)
When you reshape your mind blade, you can change it into an exotic weapon: a monk's spade (see page 136).
Ability to generate a mind blade, shape mind blade class feature,
Any time you want to reshape your mind blade using your shape mind blade class feature, you can add the monk's spade to your shape repertoire. You are proficient with your monk's spade mind blade – you are treated as if you had the feat Exotic weapon proficiency (monk's spade mind blade). The weapon is sized appropriately for you and deals damage as a monk's spade.